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The Technical Requirements For Multichannel Qam Rf Modulators, Ron D. Katznelson
The Technical Requirements For Multichannel Qam Rf Modulators, Ron D. Katznelson
Ron D. Katznelson
This paper addresses the technical requirements and implications for multichannel QAM RF modulators and upconverters and the factors that affect their proposed RF specifications. RF output power levels per channel, adjacent channel noise and broadband noise levels of such a class of multichannel modulators will be discussed. A spectral noise specification mask that is equivalent to that obtained from a combination of multiple identical masks of a standard single channel noise specifications based on power addition will be presented. The power back-off required for maintaining the proposed distortion mask levels as a function of the number of adjacent channels supported …
Delivering On The 256 Qam Promise, Ron D. Katznelson
Delivering On The 256 Qam Promise, Ron D. Katznelson
Ron D. Katznelson
The accumulation of degradation factors in the downstream channels is reviewed with focus on headend/hub transmission-related noise aggregation due to a plurality of downstream Quadrature Amplitude Modulation (QAM) transmitters and upconverters. Substantial increase in the number of QAM transmitters based on frequency agile upconverters is expected. Unlike fixed channel upconverters, these do not have narrow band filters at their output, consequently imparting appreciable levels of broadband noise on the network when several such units are combined. Based on these factors and other noise contributions, it is shown that additional impairments due to fluctuations associated with composite distortion terms on the …
Specifying And Measuring Aggregate Broadband Noise Of Catv Modulators And Upconverters, Steven I. Rubin, Andre Basovich, Brani Petrovic, Ron D. Katznelson
Specifying And Measuring Aggregate Broadband Noise Of Catv Modulators And Upconverters, Steven I. Rubin, Andre Basovich, Brani Petrovic, Ron D. Katznelson
Ron D. Katznelson
This paper discusses the practical limitations and the subtle assumptions that must be incorporated into the specifications and measurements of Aggregate Broadband Noise of CATV upconverters and digital QAM transmitters. Considerations that govern the accuracy and measurement dynamic range required for such Aggregate Broadband Noise measures are identified. Novel methods involving the separation of the Aggregate Broadband Noise measure into its composites, namely, modulated distortion noise components and other broadband noise components are discussed. Optimal ways in which such measurement techniques have been automated to enable rapid and efficient evaluation of transmitter devices are also presented along with examples of …